In addition to the subject error, your Directory Service log contains:
Source: NTDS ISAM
User : N/A
Description : NTDS (248) Unable to create the log. The drive might be read-only, out of disk space, misconfigured, or corrupted. Error -519.
This behavior will occur if you are currently logging to %SystemRoot%\Ntds\Edbffff0.log and this log has reached its' maximum size.
NOTE: When you first implement Active Directory, the transactions are logged to %SystemRoot%\Ntds\Edb.log. When this log reaches its' maximum size limit, a new %SystemRoot%\Ntds\Edb00001.log file is created. When %SystemRoot%\Ntds\Edb00001.log reaches its' maximum size limit, a new %SystemRoot%\Ntds\Edb00002.log file is created. When %SystemRoot%\Ntds\Edbffff0.log is finally created and reaches its' maximum size, no new logs can be created.
To resolve this issue:
1. Restart your Windows 2000 Active Directory server in Directory Service Restore Mode.
2. Open a CMD.EXE window.
3. Type the following commands, pressing Enter after each line:
Semantic database analysis
5. Type del /q Edb.chk and press Enter.
6. Type del /q *.log and press Enter.
7. Shutdown and restart your server.